Answer:
- <u><em>He must use 50g of the 12% solution and 30 g of the 20% solution.</em></u>
<u><em></em></u>
Explanation:
Call x the amount of <em>12% boric acid </em>solution to be used.
- The content of acid of that is: 0.12x
Since he wants to make <em>80 grams</em> of solution, the amount of <em>20% boric acid</em> solution to be used is 80 - x.
- The content of acid of that is{ 0.20(80 - x).
The final solution is <em>15% </em>concentrated.
- The content of boric acid of that is 0.15 × 80 g.
Now you have can write your equation:
Solve:
That is 50 grams of the 12% solution of boric acid.
Calculate the amount of the 20% solution of boric acid:
That is 30 grams.
Then, he must use 50g of the 12% solution and 30 g of the 20% solution.
A molecular covalent substance (such as co2) has a low melting point because the covalent bonds that hold the molecules together are weak and do not require much energy to break:- False.
What are covalent bonds ?
An electron transfer that leads to the formation of electron pairs between atoms is known as a covalent bond. When atoms share electrons, a stable balance of the repulsive and attractive forces among them is known as covalent bonding. These electron pairs are also known as bonds or shared pairs.
It is a molecular compound, which is a mixture of at least two atoms—the smallest building blocks of matter—joined by a covalent bond. These atoms are joined by a covalent bond, which is formed when electrons are shared.
Learn more about covalent bond here:-
brainly.com/question/19382448
#SPJ4
Answer:
molar mass = 180.833 g/mol
Explanation:
- mass sln = mass solute + mass solvent
∴ solute: unknown molecular (nonelectrolyte)
∴ solvent: water
∴ mass solute = 17.5 g
∴ mass solvent = 100.0 g = 0.1 Kg
⇒ mass sln = 117.5 g
freezing point:
∴ ΔTc = -1.8 °C
∴ Kc H2O = 1.86 °C.Kg/mol
∴ m: molality (mol solute/Kg solvent)
⇒ m = ( - 1.8 °C)/( - 1.86 °C.Kg/mol)
⇒ m = 0.9677 mol solute/Kg solvent
- molar mass (Mw) [=] g/mol
∴ mol solute = ( m )×(Kg solvent)
⇒ mol solute = ( 0.9677 mol/Kg) × ( 0.100 Kg H2O )
⇒ mol solute = 0.09677 mol
⇒ Mw solute = ( 17.5 g ) / ( 0.09677 mol )
⇒ Mw solute = 180.833 g/mol
355 volcanoes in the Philippines are inactive.
24 volcanoes are active
